Introduction

At the conclusion of World War II, the U.S. determined on a foreign policy of engagement with the world. The United Nations was the cornerstone of that decision. In the crafting of the thick postwar liberal international order, the president played a crucial role, and from then to the present, presidents would be central to UN activities. Woodrow Wilson had joined the idea of America’s “exceptionalism” to a new U.S. foreign policy of “internationalism.” The country rebuffed Wilson’s League of Nations but turned to a robust internationalism with FDR’s UN. But the tension of an ongoing cold war, contentious domestic politics, and a rapidly changing world challenged the initial optimism about the United Nations and the postwar order. Nonetheless, presidents, for the most part, retained a commitment to international “engagement,” even as their worldviews—whether realist, idealist, neoconservative, or neoliberal—diverged. The rise of nativist and isolationist impulses reached an apex with Donald Trump’s election in 2016. Realist, idealist, neoconservative, and liberal adversaries in erstwhile debates of a sudden joined forces to oppose Trump’s withdrawals from international commitments. The question now was whether that historic presidential-UN relationship would resume in the future. Internationalism appeared to be in the balance.